Question: $ { \left[\begin{array}{rrr}{1} & {-2} & {1} \\ {-2} & {2} & {2}\end{array}\right]+\left[\begin{array}{rrr}{2} & {0} & {-1} \\ {2} & {4} & {4}\end{array}\right] = {?} } $
To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{1}+{2} & {-2}+{0} & {1}+{-1} \\ {-2}+{2} & {2}+{4} & {2}+{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{3} & {-2} & {0} \\ {0} & {6} & {6}\end{array}\right]}$